Nitrogen Recovery from Landfill Leachate Using Lab- and Pilot-Scale Membrane Contactors : Research into Fouling Development and Membrane Characterization Effects

Funding Information: This research received funding from Ministry of the Environment in Finland RAKI2 project VN/2250/2019 and from Maa- ja vesitekniikan tuki r.y. (MVTT). Funding Information: This work was supported by Maa- ja Vesitekniikan tuki r.y. (MVTT). The authors are grateful to Aino Peltola for her assistance with the laboratory analyses. The authors are thankful to Antti Louhio’s help with designing the lab reactors. The authors would also like to acknowledge the support from Onni Lehtikuja with conducting laboratory tests. Publisher Copyright: © 2022 by the authors.Membrane contactor technology affords great opportunities for nitrogen recovery from waste streams. This study presents a performance comparison between lab- and pilot-scale membrane contactors using landfill leachate samples. Polypropylene (PP) and polytetrafluoroethylene (PTFE) fibers in different dimensions were compared in terms of ammonia (NH3) recovery on a lab scale using a synthetic ammonium solution. The effect of pre-treating the leachate with tannin coagulation on nitrogen recovery was also evaluated. An ammonia transfer on the lab and pilot scale was scrutinized using landfill leachate as a feed solution. It was found that PTFE fibers performed better than PP fibers. Among PTFE fibers, the most porous one (denoted as M1) had the highest NH3 flux of 19.2 g/m2.h. Tannin pre-treatment reduced fouling and increased NH3, which in turn improved nitrogen recovery. The mass transfer coefficient of the lab-scale reactor was more than double that of the pilot reactor (1.80 × 10−7 m/s vs. 4.45 × 10−7 m/s). This was likely attributed to the difference in reactor design. An analysis of the membrane surface showed that the landfill leachate caused a combination of inorganic and organic fouling. Cleaning with UV and 0.01 M H2O2 was capable of removing the fouling completely and restoring the membrane characteristics.Peer reviewe